Proceedings of the Columbus Horticultural Society. 45 



south and from the west — the latter the more recent of our 

 accessions. In the lists which arc to follow the various com- 

 ponents will appear. 



It may be said that the topography exerts a great influence. 

 All appreciate this ; at the same time must we not consider 

 the effects of pre-glacial and interglacial drainage when we 

 would write a full history of the Ohio plants ? As the glacial 

 advance must have forced plants south of us, which upon the 

 glacial recession again returned, so likewise must there have 

 been carried forward the plants which grew beside our Presi- 

 dent's great, pre-glacial, north-flowing river of this region ; 

 some of them in turn come back to us as plants from the 

 south. Liquidambar and Phoradendron spring into mind 

 at once. They also represent two different means by which 

 the migration of land plants are effected. The Ohio plants, 

 like the people who followed them, by reason of the eastern 

 gateway which the settlers found to the vast Valley of the 

 Mississippi, are cosmopolitan in character. Ecology and 

 PLthnology alike make record of these blended races. 



Some few words of explanation will probably be necessary in 

 order that the classification as to direction of migration of 

 plants may be fully understood. In making up these lists it 

 has been our aim to take only those plants concerning which 

 there can be little doubt as to the direction of their move- 

 ment ; yet, we may have included some that might well have 

 been omitted and conversely. We have also indicated those 

 which occur in Europe, etc. Introduced or naturalized plants 

 are collected in a separate list ; the number of these may 

 doubtless be as much of a surprise to others as it was to us. 



Topographical and hydrographical features have been con- 

 sidered in making the lists. Thus, for example, we may have 

 plants extending from Nova Scotia to Michigan and south in 

 the mountains to Georgia or Alabama, yet these plants appear 

 to have come to us from the northeast, as their southern limits 

 are confined to the mountain districts. Again, we may have 

 plants ranging from Texas to P'lorida and along the coast to 

 New Jersey, or probably even to Massachusetts. Where such 

 plants have made their way into our state we naturally con- 

 clude that they are southern, having made their advance along 

 the river valleys and not across the mountains. 



As for plants from the east and southeast we have taken 

 only those of a limited area; those of a more extended range 

 being classed with the plants from the northeast and south 

 respectivel}'. 



In making up the lists of plants that have come in from the 

 north, we met with many difficulties, owing to the fact that 



